Rocker box lubrication system



April 4, 1950 G. B. DU Bols r-:TAL

RocxER Box LUBRICATION SYSTEM 2 Sheets-Sheet 1 Filed June 26, 1944INVENTOR. EE B- Du BDIE- M E- EVENE- April 4, 1950 G. B. Du Bols Erm.

RocKER Box LUBRICATION SYSTEM 2 Sheetssheet 2 June 26' VENTORS. Du BEII5WILLIAM EVENE- ATTEIRNEY Patented Apr. 4, 1950 UNITED STATES T-ENTOFFICE Ovens, Midland Park, N. J.,

assgnors to Wright Aeronautical Corporation, a corporation of New YorkApplication June 26, 1944, Serial No. 542,120

12 Claims.

This invention relates to valve gear lubrication, and is particularlydirected to means for lubricating the valve gear of the lower cylindersof a radial cylinder engine.

The valve gear for each cylinder valve of a radial cylinder enginegenerally comprises a rocker arm, pivotally mounted on the cylinder headand disposed within a rocker box, the rocker arm having its one endoperatively engaging a valve stem and its other end operatively engaginga hollow push rod, reciprocated by an engine driven cam. The valve gearfor the valves of the upper engine cylinders are generally pressurelubricated by metered quantities of oil fed through the hollow push rod,the oil draining by gravity back into the engine crank case from therocker box through a tubular housing surrounding the push rod.Obviously, such a gravity return oil circulating system cannot be usedfor lubricating the valve gear of any of the lower engine cylinders. Thevalve gear of these lower engine cylinders are conventionally lubricatedby allowing a limited quantity of oil to drain into the rocker boxes,and therefore, there is no circulation of oil through such valve gear.Accordingly, it is an object of this invention to provide a new andimproved method and means for lubricating the valve gear of the lowercylinders of a radial cylinder engine. It is a further object of thisinvention to provide a new lubrication system for the valve gear of thelower engine cylinders whereby oil is circulated through such valve gearand their associated rocker boxes.

Specically, the invention comprises means to supply lubricating oildirectly to the rocker box housing through the annular passage betweenthe push rod and the usual tubular casing surrounding the push rod. Withthis arrangement, oil accumulates within the rocker box, and byproviding a bleed opening in the Valve tappet at the upper end of thepush rod, the gas pressure within the rocker is effective to force theoil into the rocker arm bearing, through the oil passages in the rockerarm and push rod and out into the engine crank case through theaforementioned bleed opening. It is also an object of this invention inan alternative proposal to utilize the reciprocal movement of the Valvegear for operating a pump to help remove the oil from the rocker box.

Other objects of this invention will become apparent upon reading theannexed detailed description in connection with the drawing in which:

Figure 1 is a schematic front view of a radial cylinder engine;

Figure 2 is a sectional view through the valve gear of a lower cylinderof the engine and embodying the invention;

Figure 3 is an enlarged view of the valve tappet embodied in Figure 2;

Figure 4 is a development of the exterior of a portion of the valvetappet;

Figure 5 is a view illustrating a modification of a portion of Figure 2;

Figure 6 is a view similar to Figure 2 of a modii'lcation;

Figure 7 is a sectional view of a further modication; and

Figure 8 is a sectional View taken along line 8 8 of Figure '7.

Referring to the drawing, a conventional radial cylinder internalcombustion engine I0 is provided with a crank case I2 about which aplurality of radially disposed cylinders I4 are mounted. Each cylinderis provided with a cylinder head I6, and a pair of rocker boxes I8 areintegrally formed therewith for the cylinder intake and exhaust valves.In each rocker box, a rocker arm 2l] is pivotally mounted about a rockerarm bolt 2L carried by the walls of the rocker box. One end of eachrocker arm is provided with a roller 22, adapted to engage the end of avalve stem 24 of a valve 26. The valve 26 is slidably mounted within avalve guide 28 in the cylinder head and is urged toward closed positionby spring means 313.

The other end of the rocker arm is provided with an adjusting nut 32having a spherical bearing seat adapted to engage the outer end of ahollow push rod 34. The other end of the push rod is engaged by thespherical seat formed at one end of a hollow valve tappet comprisinghollow interfitted members 36 and 31 urged apart by a spring 38. Thevalve tappet 36, 3l is slidably mounted within a valve tappet guide 39carried by the engine crank case i2. The other end of the valve tappet3, 31 is provided with cam follower roller 4?, which is arranged forengagement by engine driven ca m means 4H. A tubular casing 42 isdisposed about the push rod 34 and is secured at one end to the valvetappet guide 39 and at its other end to its associated rocker box. Thestructure so far described is quite conventional.

In the conventional lubricating arrangement, the supply of oil for therocker boxes of the lower cylinders consists of the oil which leaksoutward between the valve tappet socket and valve guide parts, therebeing no other passages for either supply or return of oil. In such anarrangement, the supply of oil can be controlled only by indirect means,and there is no circulation and return of oil from these lower rockerboxes.

In the present invention, oil for lubricating the valve gear of thelower engine cylinders is supplied under pressure to the passage 44formed in the crank case supporting structure about each valve tappetguide 39. Each valve tappet guide 39 is provided with a radial opening46 communicating with the supply passage 44, and during engineoperation, an annular groove 48 about the exterior surface of the valvetappet member 31 is periodically brought into alignment with thisopening 46. The valve tappet member 31 is also provided with an axiallyextending flat or groove 50 on its exterior surface, establishingcommunication between the groove 48 and the interior of the tubularcasing 42. Thus, when the annular groove 48 is in communication with theopening 46, oil is fed therethrough to the fiat 50, tubular casing 42,and thence into the rocker box connected thereto. With this constructionthe axial position of the annular groove 48 about the valve tappetdetermines the length of time the groove is in communication with thepassage 46 during each tappet actuation, thereby controlling thequantity of oil metered to the rocker boX.

In Figure 2, the valve tappet 36, 31 is shown in its valve opening oractuated position, and accordingly, the annular groove 48 is incommunication with the passage 46, while in the enlarged view of Figure3 the valve tappet is 4 tive disposition of the annular groove 48 andthe groove or flat 5D is best seen in the development of the exteriorsurface of the tappet member 31 in Figure 4.

The push rod 34 is hollow, and its lower end communicates with a passageleading to the rocker arm roller bearing 52, while its upper endcommunicates with the hollow valve tappet 35, 31 which is provided witha hole 54 communicating with the interior of the crankcase around theroller 4U and through the open inner end 55 of the tappet guide 39. Thehole 54 is disposed at the inner end of the tappet member 31 directlyunder the cam follower roller 40. That is, the passage 45, the hollowpush rod, the hollow valve tappet, and hole 54, together denne a ventpassage establishing communication between a point within the rocker boxand the crank case. Therefore, with an excess quantity of oil suppliedto the rocker box, the rocker box will ll with oil approximately to thelevel indicated at 5I in Figure 2, at which level the rocker box end ofthe vent passage is submerged in the oil. The gas pressure within therocker box will prevent the oil from rising appreciably beyond thislevel, by forcing the oil out into the crank case through this ventpassage.

If the valve 26 is an exhaust valve, there will always be a substantialgas pressure within the rocker box, because there always is a tendencyfor the transmission of the engine exhaust pressure into the rocker boxthrough the space between the valve stem and valve guide. Similarly, ifthe valve 26 is an intake valve and the engine is provided with asupercharger maintaining a manifold pressure above atmospheric pressure,there always is a tendency for the transmission of this manifoldpressure into the rocker box through the space between the valve stemand its guide. The provision of such a supercharger is general practiceon aircraft engines.

With the above described arrangement, although the groove 48 ispositioned so as to meter a surplus quantity of oil to the rocker box,the gas pressure within the rocker box prevents the rocker box fromfilling up completely by forcing the excess oil out through a dischargepassage into the crank case. In other words, there is a continualcirculation of oil through the rocker box flood lubricating the rockerarm bearing, and

in addition, the rocker box does not fill up with oil.

By discharging the oil through the valve tappet opening 54 into thecrank case, the valve tappet guide 39 provides a stand pipe extendinginto the crank case, thereby preventing drainage of crank case oil backinto the rocker box. Also, if desired, an oil passage 5B may be providedthrough the back of the rocker arm adjusting nut 32 as illustrated inFigure 5. This latter arrangement facilitates the return of oil to thecrank case by by-passing the passage 45 in the rocker arm.

Figure 6 illustrates a further modification in which an inertia pump isincorporated within the push rod in order to help remove the oil fromthe rocker box. This pump comprises a hollow spring balanced plungermember 60 slidably disposed within the push rod and urged to anintermediate position therein by springs 62 and 64, respectivelydisposed between the plunger and the two ends of the push rod. Aball-typc check valve 66 is disposed between the one end of the spring62 and the adjacent end of the plunger 6D, and a second ball-type checkvalve 68 is disposed between one end of the spring 64 and the adjacentend of the push rod. With this arrangement, the inertia plunger 60 tendsto stand still while the push rod reciprocates and therefore, on thedownstroke of the push rod, oil is drawn into the lower or outer end ofthe push rod and is forced out of the upper or inner end of the pushrod, while on the upstroke of the push rod, oil is displaced through theplunger 60 from its lower end to its upper end. Except for the provisionof the inertia pump in the hollow push rod, the modification of Figure 6is similar to Figure 2 and like parts have been designated by likereference numerals.

Instead of providing an inertia-type pump within the push rod asillustrated in Figure 6, a conventional piston-type pump may be disposedwithin the rocker box for pumping the rocker box oil back of the crankcase through the hollow push rod. Such an arrangement is illustrated inFigures 7 and 8 in which a pump cylinder 16 is carried by the rocker boxcover 12, and a piston 14 disposed within the cylinder 10 is urgedoutwardly against the rocker arm 15 by a spring 16. A passage 1B formedwithin the rocker box cover opens into the pump cylinder through openingand into the rocker box through a check valve 82. If desired, a lightspring (not shown) may urge the valve 82 upwardly against its seat. Thepassage 18 also communicates with a passage 84 extending up one sidewall on the rocker. box cover. The side wall passage 84 is counterboreclat 86 for receiv ing a check valve 88 urged downwardly against its seatby a spring 90. The passage 84 communicates with a passage 92 in theside wall oi' the rocker box proper which leads up into communicationwith a hollow rocker arm bolt 94 and a radial opening 95 establishescommunication between the hollow rocker arm bolt and the rocker armbearing 95 as best seen in Figure 8. A passage Sl extends from therocker arm bearing 95 to the hollow push rod as in the previousmodifications.

With the construction of Figures 7 and 8, upon reciprocation of therocker arm, the pump piston operates to pump oil out through the checkvalve 88 to the rocker arm bearing and through the rocker arm passage 91and the hollow push rod into the engine crank case. During thedownstroke of the piston 14, the check valve 82 closes, while the pistonforces the oil within the cylinder I0 up through the check valve l88 andthence through the rocker arm passage 97 and the hollow push rod intothe engine crank case. On the spring return stroke of the piston 14, thecheck valve 88 closes to prevent the return of oil back into the rockerbox from the push rod, while the check valve 82 opens to permit the pumpcylinder 70 to refill with oil. As illustrated, the rocker arm isprovided with a plane bearing 95, which type of bearing has much lessend leakage than the roller bearings illustrated in Figures 2 and 6. Ifa roller bearing were provided in Figures 7 and 8, it might be necessaryto provide bearing end seals in order to limit the leakage of oil outthrough the bearing ends.

In all modifications, lubricating oil enters the rocker boxes for thelower cylinders to lubricate the rocker arm bearing, and the oil levelin these rocker boxes rises until it closes the lower or outer end ofthe escape passage of the rocker box gases through the associated hollowpush rods. The escaping rocker box gas pressure, either alone orassisted by pumps, prevents the oil from rising above this level byforcing the surplus oil up through the push rods into the crank case. Inthis way the rocker arm bearings for the lower cylinders are floodlubricated, and yet the rocker box does not fill up with oil, thesurplus oil returning to the engine crank case through the hollow valveoperating push rods.

While we have described our invention in detail in its present preferredembodiment, it will be obvious to those skilled in the art, afterunderstanding our invention, that various changes and modifications maybe made therein without departing from the spirit or scope thereof. Weaim in the appended claims to cover all such modifications and changes.

We claim as our invention:

l. In an internal combustion engine, a Valve, a rocker arm operativelyengaging said valve7 a housing enclosing said arm` a hollow push rodmounted for reciprecation by said engine and operatively engaging saidarm, a tubular casing surrounding said push rod, means for supplyinglubricating oil to said housing through said tubular casing, and meansdisposed within said hollow push rod and responsive to reciprocationthereof for removing lubricating oil from said housing through said pushrod.

2; In an engine having a crank case, a valve, a valve gear for operatingsaid valve comprising a, rocker arm` and a hollow push rod, a housingfor said rocker arm into which the stem of said valve projects foroperative engagement by said rocker arm, said push rod being mounted forreciprocation by said engine and extending. in a direction downwardlyfrom the engine crank case into said housing into operative engagementwith said rocker arm, a tubular casing surrounding said push rod, meansto supply lubricating oil to said housing through the annular passagewithin the tubular casing about the push rod, and pump means responsiveto operation of said valve gear for removing lubricating oil from saidhousing through said push rod.

3. In an internal combustion engine having a crankcase, a valve, a valveoperating mechanism, a housing for said mechanism, a push rod extendingin a direction downwardly from said orankcase to said housing andoperatively engaging said valve operating mechanism for operating saidvalve, a tubular casing surrounding said push rod and extending in adirection downwardly from said crankcase to said housing but terminatingshort of the bottom end of said push rod means for supplying lubricatingoil to said housing through the annular passage within the tubularcasing about the push rod, and means for returning oil from said housingto said crankcase, said last mentioned means including an oil passagewayextending longitudinally through said push rod and communicating at itsupper end with the interior of said crankcase and communicating at itslower end with the interior oi said housing.

(i, In an internal combustion engine having a crankcase, an enginecylinder` valve, a housing into which the stern of said valve projects,a rocker arm within said housing operatively engaging said valve stem, avalve operating push rod extending in a direction downwardly from saidcrankcase into said housing and operatively engaging said rocker arm, atubular casing surrounding said push rod and extending in a directiondownwardly from said crankcase to said housing but terminating short ofthe bottom end of said push rod, means for supplying lubricating oil tosaid housing through the annular passage within the tubular casing aboutthe push rod. and means for returning oil from said housing to saidcrankcase, said last mentioned means including an oil passagewayextending longitudinally through said push rod and communicating at itsupper end with the interior of said crankcase and communicating at itslower end with the interior of said housing.

5. In an internal combustion engine having a crankcase. an enginecylinder valve, a housing into which the stem of said valve projects, arocker arm within said housing operatively engaging said valve stem, avalve operating push rod extending in a direction downwardly from saidcrankcase into said housing and having one end operatively engaging saidrocker arm, a valve tappet slidably supported by said crankcase andoperatively engaging the other end of said push rod, a tubular casingsurrounding said push rod and extending in a direction downwardly fromsaid crankcase to said housing but terminating short of the bottom endofsaid push rod, means for supplying lubricating oil to said housingthrough the annular passage within the tubular casing about the pushrod. and a passageway for returning oil from said housing to saidcrankcase, said passageway including a passage extending longitudinallythrough said push rod anda passage extending through saidtappet andcommunicating with said push rod passage,l said tappet; projecting asubstantial distance into said crankcase with the discharge end of saidtappet passage opening into the crankcase adjacent the inner end of saidtappet.

6. In an engine having a crankcase; a valve; a housing; valve operatingmechanism within said housing operatively connected to said valve; avalve-operating push rod mounted for reciprocation by said engine andextending in a direction downwardly from said engine crankcase into saidhousing into operative engagement with said mechanism, said push rodbeing hollow to form at least a portion of a passage between saidhousing and crankcase; a tubular casing surrounding said push rod toform an annular space about said push rod; means for supplyinglubricating oil to said housing through said annular space, said housingbeing subjected to a gas pressure, during engine operation, in excess ofthe pressure within said crankcase, the arrangement being such that thepressure differential between said housing and crankcase urges oil fromsaid housing through said passage when the oil within said housingcovers the housing end of said passage.

7. In an internal combustion engine having a crankcase; a valve; valveoperating mechanism connected to said valve; a housing for saidmechanism; a hollow push rod mounted for reciprocation by said engineand having one end operatively engaging said mechanism for operatingsaid valve; means'for supplying lubricating oil to said housing; andpump means disposed within said hollow push rod and responsive toreciprocation thereof for removing lubricating oil from said housingthrough said rod.

8. In an internal combustion engine having a crankcase; a valve; valveoperating mechanism connected to said valve; a housing for saidmechanism, said mechanism and its housing beingl disposed below saidcrankcase; a hollow valve operating push rod mounted for reciprocationby said engine and disposed between said cranking from said passage andthrough said annular space; and a passageway extending longitudinallythrough said push rod for returning oil from said housing to saidcrankcase.

10. In an internal combustion engine having a crankcase; a valve; valveoperating mechanism connected to said valve; a housing for saidmechanism, said mechanism and its housing being disposed below saidcrankcase; a push rod disposed between said crankcase and housing andhaving one end operatively engaging said mechanism for operating saidvalve in response to reciprocation of said rod; a sleeve carried by saidcrankcase; a valve tappet slidably supported by said crankcase withinsaid sleeve and operatively engaging the other end of said push rod forreciprocating said rod; a tubular casing surrounding said push rod andhaving one end forming a continuation of said sleeve and having itsother end opening into said housing, said sleeve and tappet having apassage therebetween communicating at one end with the annular spacewithin said tubular casing about said push rod; an oil supply passagewayintermittently communicating with the other end of said passage duringreciprocation of said tappet whereby lubricating oil is supplied to saidhousing from said passage and thence through said annular space; and apassageway for returning oil from said housing to said crankcase, saidpassageway including a passage extending longitudinally through saidpush rod and a passage extending through said tappet and communicatingwith said push rod passage, said tappet projecting a substantialdistance into said crankcase with the discharge end of said tappetpassage opening into the crankcase adjacent the inner end of saidtappet.

11. In an engine having a crankcase, a valve, a housing into which thestem of said valve projects, valve operating mechanism within saidhousing operatively engaging said valve stem, a valve-operating push rodmounted for reciprocation by said engine and extending in a directionCaSe and housing and having 011e end Operatvly downwardly from saidengine crankcase into said engaging said mechanism; a tubular casingsurrounding said push rod; means for supplying lubricating oil to saidhousing through the annular space Within the tubular casing about thepush rod; and pump means disposed within thev hollow push rod andresponsive to reciprocation of said rod for removing lubricating oilfrom said housing through said rod.

9. In an internal combustion engine having a crankcase; a valve; valveoperating mechanism having one end operatively engaging said mech-'anism for operating said valve in response to reciprocation of saidrod; a sleeve carried by said crankcase; a valve tappet slidablysupported by said crankcase within said sleeve and operatively engagingthe other end of said push rod for reciprocating said rod; a tubularcasing surrounding said push rod and having one end forming acontinuation of said sleeve and having its other end opening into saidhousing, said sleeve and tappet having a passage therebetweencommunieating with the annular space within said tubular casing aboutsaid push rod; an oil supply passageway intermittently communicatingwith said passage during reciprocation of said tappet wherebylubricating oil is supplied to said houshousing and into operativeengagement with said mechanism, said push rod being hollow to form atleast a portion of a passage between said housing and crankcase, atubular casing surrounding said push rod, means for supplyinglubricating oil to said housing through the annular space within thetubular casing about the push rod, said housing being subjected to a gaspressure during engine operation in excess of the pressure within saidcrankcase, the arrangement being such that the pressure diierentialbetween said housing and crankcase urges oil from said housing throughsaid passage when the oil within said housing covers the housing end ofsaid passage.

12. In an engine having a crankcase, an engine exhaust valve, a housinginto which the stem of said valve projects, valve operating mechanismwithin said housing operatively engaging said valve stem, avalve-operating push rod mounted for reciprocation by said engine andextending in a direction downwardly from said engine crankcase into saidhousing and into operative engagement with said mechanism, said push rodbeing hollow to form at least a portion of passage between said housingand crankcase, a tubular casing surrounding said push rod and extendingin a direction downwardly from said crankcase to said housing butterminating short of the bottom end of the push rod, means for Supplyinglubricating oil to said housing through the annular space Within thetubular casing about the push rod, said housing being subjected to a gaspressure during engine operation resulting from leakage of engineexhaust gases therein 5 from around said valve stern, the gas pressuredifferential between said housing and crankcase urging oil from saidhousing through said passage when the oil Within said housing covers thehousing end of said passage. 10

GEORGE B. DU BOIS. WILLIAM G. OVENS.

REFEREN CES CITED The following references are of record in the 15 le ofthis patent:

Number Number 10 UNITED STATES PATENTS Name Date Marmon Ii'eb- 12, 1918Pirinoli Nov. 29, 1932 Davis June 9, 1936 Hersey et al Mar. 9, 1937Willgoos July 12, 1938 Morehouse Dec. 29, 1942 Doman Jan. 9, 1945 DomanAug. 7, 1945 FOREIGN PATENTS Country Date Italy July 18, 1936 FranceDec. 16, 1925

